Method for separating high molecular weight gases from a combustion source

ABSTRACT

High molecular weight (HMW) gases are separated from an exhaust gas of a combustion source using a blower and an interior vent within the exhaust stack. The interior vent includes a vent wall having a top portion attached to the interior surface of the exhaust stack along the entire inner perimeter of the exhaust stack and a lower portion that extends downward into the exhaust stack to form an annular space or gap between the vent wall and the interior surface of the exhaust stack, and at least one opening in the interior surface of the exhaust stack between the top and bottom portions of the vent wall. The blower creates a tangential flow of the exhaust gas with sufficient centrifugal force to concentrate substantially all of the HMW gases along the inner surface of the exhaust stack. A transfer pipe removes the HMW gases from the interior vent.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.13/314,110, filed Dec. 7, 2011, which claims priority to U.S.Provisional Application Ser. No. 61/420,751, filed Dec. 7, 2010, theentire contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to the field of separation andsequestration of combustion exhaust gases.

BACKGROUND OF THE INVENTION

Combustion systems have come under increased scrutiny for toxicemissions which are a by-product of the combustion process. Dependingupon the extent of the combustion, carbon monoxide and NO_(X) may beemitted at unacceptable levels. Carbon monoxide levels are normallycontrolled through complete combustion resulting in carbon dioxide. Infact, in years past, carbon dioxide was measured to determine theefficiency of the process. Traditionally, NO_(X) and other VOC emissionshave been either controlled by cleaner fuels or techniques that reduceformation. Recently, because of the push for alternative and renewablefuels, carbon dioxide being the only component here-to-fore notregulated has come under increased scrutiny (green house gases, carbonfootprints and global warming).

The problem is, burning fossil fuels makes carbon dioxide, and burningfossil fuels more efficiently makes even more carbon dioxide. NO_(X) andSO_(X) along with other pollutants, which comprise only parts permillion in the resulting emissions, are controlled by many effectivemethods; but there few effective methods of controlling CO₂ emissions.

Since CO₂ comprises from 10 to 15% of the exhaust or flue gas by volume,it is impractical to treat it without separating it from the remaininggases. Several systems have been developed to reduce the CO₂, and insome cases to concentrate the gas. Increasing the amount of hydrogen inthe fuel will reduce the fraction of CO₂ in the flue gas, since hydrogencombustion does not produce CO₂. If the exhaust or flue gas isrecirculated and the incoming fuel is mixed with pure O₂ the nitrogen inthe air is eliminated. And, with enough recycling of the exhaust or fluegas, the CO₂ is concentrated to higher levels. After concentration,there are accepted methods of either using or treating the CO₂. Theburning of the hydrogen simply reduces the CO₂. These known methods arequite inflexible and require reconfiguring the combustion equipment. Inmany cases, very flexible control algorithms will need to be employed toadjust the various fuel-air curves needed for the ever changing fuelcompositions. The production or purchase of the hydrogen or oxygenneeded in these processes also tend to make them impractical.

SUMMARY OF THE INVENTION

The present invention provides a system and method for separating highmolecular weight gases, such as CO₂, from any combustion source. Morespecifically, the present invention imparts centrifugal force on theexhaust or flue gas by spinning the exhaust or flue gas with enoughvelocity to remove the heavy components, such as CO₂, to the outsidediameter of the stack and removing it thru an annular space or gapformed by an interior vent. The spin needed for the centrifugal actionmay be imparted by using a blower to remove the gas tangentially fromone side of the stack and blowing it tangentially back into the stack onthe other side. The use of a stationary tubulator, or spin vanes, oractual in-stack centrifuge may be necessary in addition to the blower.Note that the velocity of the system may be varied to accommodatevarious fuels and flue gas mixtures. Moreover, the system may be fittedto stacks of virtually any size or flow. As a result, the presentinvention provides a simple process to take care of the hardest and mostexpensive step in controlling CO₂. Many treatment options are availableafter separation.

One embodiment of the present invention provides a method for separatinghigh molecular weight gases from an exhaust gas of a combustion sourceby providing (a) a blower attached to an intake of an exhaust stack toreceive the exhaust gas from the combustion source, (b) an interior ventwithin the exhaust stack comprising (i) a vent wall having a top portionattached to the interior surface of the exhaust stack along the entireinner perimeter of the exhaust stack and a lower portion that extendsdownward into the exhaust stack to form an annular space or gap betweenthe vent wall and the interior surface of the exhaust stack, and (ii) atleast one opening in the interior surface of the exhaust stack betweenthe top and bottom portions of the vent wall, and (c) a transfer pipeconnected to the at least one opening in the interior surface of theexhaust stack. A tangential flow of the exhaust gas is created withinthe exhaust stack using the blower, wherein the blower impartssufficient centrifugal force on the exhaust gas to concentratesubstantially all of the high molecular weight gases along the innersurface of the exhaust stack. The high molecular weight gasesconcentrated along the inner surface of the exhaust stack are collectedusing the interior vent. The high molecular weight gases are removedfrom the interior vent using the transfer pipe.

In addition, the present invention provides a system for separating highmolecular weight gases in an exhaust stack from an exhaust gas of acombustion source using a blower, an interior vent and a transfer pipe.The blower is attached to an intake of the exhaust stack to receive theexhaust gas from the combustion source and create a tangential flow ofthe exhaust gas within the exhaust stack. The blower imparts sufficientcentrifugal force on the exhaust gas to concentrate the high molecularweight gases along the inner surface of the exhaust stack. The interiorvent is disposed within the exhaust stack and collects the highmolecular weight gases concentrated along the inner surface of theexhaust stack. The interior vent includes (i) a vent wall having a topportion attached to the interior surface of the exhaust stack along theentire inner perimeter of the exhaust stack and a lower portion thatextends downward into the exhaust stack to form an annular space or gapbetween the vent wall and the interior surface of the exhaust stack, and(ii) at least one opening in the interior surface of the exhaust stackbetween the top and bottom portions of the vent wall. The transfer pipeis connected to the at least one opening in the interior surface of theexhaust stack to remove the high molecular weight gases from theinterior vent.

Moreover, the present invention provides a system for separating highmolecular weight gases from an exhaust gas of a combustion source usingan exhaust stack, a blower, an interior vent and a transfer pipe. Theblower is attached to an intake of the exhaust stack to receive theexhaust gas from the combustion source and create a tangential flow ofthe exhaust gas within the exhaust stack. The blower imparts sufficientcentrifugal force on the exhaust gas to concentrate the high molecularweight gases along the inner surface of the exhaust stack. The interiorvent is disposed within the exhaust stack and collects the highmolecular weight gases concentrated along the inner surface of theexhaust stack. The interior vent includes (i) a vent wall having a topportion attached to the interior surface of the exhaust stack along theentire inner perimeter of the exhaust stack and a lower portion thatextends downward into the exhaust stack to form an annular space or gapbetween the vent wall and the interior surface of the exhaust stack, and(ii) at least one opening in the interior surface of the exhaust stackbetween the top and bottom portions of the vent wall. The transfer pipeis connected to the at least one opening in the interior surface of theexhaust stack to remove the high molecular weight gases from theinterior vent. The high molecular weight gases have a molecular weightgreater than 35 and at least 85% of the high molecular weight gases areconcentrated along the inner surface of the exhaust stack. The annularspace or gap has an area of approximately 10% of a cross-sectional areaof the exhaust stack. The at least one opening is positioned at a heightabove the bottom of the exhaust stack approximately equal to threediameters of the exhaust stack. The blower causes the exhaust gases tospin around the exhaust stack at least five times within a heightapproximately equal to one diameter of the exhaust stack.

The present invention is described in detail below with reference to theaccompanying drawings which are not to scale.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and further advantages of the invention may be betterunderstood by referring to the following description in conjunction withthe accompanying drawings, in which:

FIGS. 1A, 1B and 1C are a cross sectional side view (FIG. 1A), across-sectional top view at cross section E-E (FIG. 1B), and across-sectional bottom view at cross section F-F (FIG. 1C) of a systemfor separating high molecular weight (HMW) gases in an exhaust stack inaccordance with one embodiment of the present invention;

FIGS. 2A, 2B and 2C are a cross sectional side view (FIG. 2A), across-sectional top view at cross section E-E (FIG. 2B), and across-sectional bottom view at cross section F-F (FIG. 2C) of a systemfor separating high molecular weight (HMW) gases in an exhaust stack inaccordance with another embodiment of the present invention;

FIGS. 3A, 3B and 3C are a cross sectional side view (FIG. 3A), across-sectional top view at cross section E-E (FIG. 3B), and across-sectional bottom view at cross section F-F (FIG. 3C) of a systemfor separating high molecular weight (HMW) gases in an exhaust stack inaccordance with one embodiment of the present invention;

FIG. 4 is a flow chart of a method for separating high molecular weight(HMW) gases from an exhaust gas in accordance with one embodiment of thepresent invention; and

FIG. 5 is a block diagram of a system incorporating the embodiments ofthe present invention.

DETAILED DESCRIPTION OF THE INVENTION

While the making and using of various embodiments of the presentinvention are discussed in detail below, it should be appreciated thatthe present invention provides many applicable inventive concepts thatcan be embodied in a wide variety of specific contexts. The specificembodiments discussed herein are merely illustrative of specific ways tomake and use the invention and do not delimit the scope of theinvention.

The present invention provides a system and method for separating highmolecular weight gases, such as CO₂, from any combustion source. Morespecifically, the present invention imparts centrifugal force on theexhaust or flue gas by spinning the exhaust or flue gas with enoughvelocity to remove the heavy components, such as CO₂, to the outsidediameter of the stack and removing it thru an annular space or gapformed by an interior vent. The spin needed for the centrifugal actionmay be imparted by using a blower to remove the gas tangentially fromone side of the stack and blowing it tangentially back into the stack onthe other side. The use of a stationary tubulator, or spin vanes, oractual in-stack centrifuge may be necessary in addition to the blower.Note that the velocity of the system may be varied to accommodatevarious fuels and flue gas mixtures. Moreover, the system may be fittedto stacks of virtually any size or flow. As a result, the presentinvention provides a simple process to take care of the hardest and mostexpensive step in controlling CO₂. Many treatment options are availableafter separation.

The typical constituent parts of exhaust or flue gas (usedinterchangeably) are as follows: the molecular weight of CO₂ is 44 andit comprises 10-15% of flue gases, the molecular weight of N₂ is 28 andit comprises approximately 78% of flue gases, the molecular weight of O₂is 32 and it comprises approximately 3% of flue gases, the molecularweight of H₂O is 18 and it comprises approximately 10-15% of flue gases,and the molecular weight of CO is 28 and it is normally a negligiblepercentage of the flue gas. These numbers indicate the CO₂ will need tobe basically separated from the N₂ with a differential molecular weightof 16. After the CO₂ is separated from the flue gases, it can becompressed, injected into the ground, or used for other processes. Inone embodiment of the present invention, the CO₂ is collected in a tankand then flowed up thru bubble trays containing sodium hydroxide whichwill cause the CO₂ to combine and produce sodium carbonate which can becollected for use otherwise. This embodiment is particularly useful inrefineries and chemical plants where sodium hydroxide is commonly usedin their processes (sometimes called “caustic soda”). After the sodiumhydroxide is used, the plants use acid to reduce the used sodiumhydroxide to a neutral PH so it can be disposed of. Using this byproductdoes not require the purchase of gases and eliminates a disposalproblem.

Now referring to FIGS. 1A, 1B and 1C, a cross sectional side view (FIG.1A), a cross-sectional top view at cross section E-E (FIG. 1B), and across-sectional bottom view at cross section F-F (FIG. 1C) of a system100 for separating high molecular weight (HMW) gases 112 in an exhauststack 102 from an exhaust gas 104 of a combustion source in accordancewith one embodiment of the present invention are shown. A blower 106 isattached to an intake 108 of the exhaust stack 102 to receive theexhaust gas 104 from the combustion source (502, FIG. 5) and create atangential flow 110 of the exhaust gas 104 within the exhaust stack 102.The blower 106 imparts sufficient centrifugal force on the exhaust gas104 to concentrate the high molecular weight gases 112, such as CO₂ orother gases having a higher molecular weight than N₂ or O₂ (e.g.,greater than 35), along the inner perimeter or surface 114 of theexhaust stack 102. As used herein, “along the inner perimeter or surfaceof the exhaust stack” means an area within the exhaust stack 102 that ismuch closer to the inner surface 114 of the exhaust stack 102 than tothe center of the exhaust stack 102. In other words, the high molecularweight gases 112 are concentrated near, towards or proximate to theinner surface 114 of the exhaust stack 102. The low molecular weightgases 130 exit through the top of the exhaust stack 102.

Typically, the blower 106 causes the exhaust gases 104 to spin aroundthe interior of the exhaust stack 102 at least five times within aheight approximately equal to one diameter (D) of the exhaust stack 102.As shown, the blower 106 is external to the exhaust stack 102 and isconnected to the intake 108 of the exhaust stack 102 with a first pipe116. A second pipe 118 connects the blower 106 to the bottom of theexhaust stack 102 at a point 120 approximately opposite to the intake108 and in line with the tangential flow 110 in order to create thesufficient centrifugal force on the exhaust gas 104. The use of astationary tubulator, or spin vanes, or actual in-stack centrifuge maybe necessary in addition to the blower 106.

An interior vent 122 within the exhaust stack 102 collects the highmolecular weight gases 112 concentrated along the inner surface 114 ofthe exhaust stack 102. The interior vent 122 includes: (i) a vent wall122ab having a top portion 122a attached to the interior surface 114 ofthe exhaust stack 102 along the entire inner perimeter of the exhauststack 102 (e.g., the top portion 122a is attached to the inner surface114 along any side cross section of the exhaust stack 102) and a lowerportion 122b that extends downward into the exhaust stack 102 to form anannular space or gap 124 between the vent wall 122 lower portion 122band the interior surface 114 of the exhaust stack 102; and (ii) at leastone opening 122c in the interior surface 114 of the exhaust stack 102between the top 122a and bottom lower 122b portions of the vent wall 122122ab. A transfer pipe 128 is connected to the at least one opening 122cin the interior surface 114 of the exhaust stack 102 to remove the highmolecular weight gases 112 from the interior vent 122. The at least oneor more openings 122c can be holes, slots, or any other geometricallyshaped passageway. Moreover, more than one transfer pipe 128 can beused. The lower portion 122b of the vent wall 122 122ab can besubstantially parallel to the interior surface 114 of the exhaust stack102, curved or angled with respect to the interior surface 114 of theexhaust stack 102. Note that the top portion 122a of the interior vent122 does not have to be aligned with a horizontal plane of the exhauststack 102. For example, the top portion 122a can be angled from thehorizontal plane in accordance with the tangential flow 110 (top portion122a on the opposite side of the exhaust stack 102 from the opening 122cpositioned lower than the top portion 122a adjacent to the opening122c). For example, the top portion 122a can form one or more spiralsdown from the one or more openings 122c. In addition, an optional baffleor guide 122d proximate to the at least one opening 122c can be used todirect the flow of the high molecular weight gases 112 from the interiorvent 122 into the transfer pipe 128. The baffle or guide 122d can bestraight, angled, curved or any other shape and orientation to moreefficiently guide the high molecular weight gases 112 into the transferpipe 128.

The dimensions (A, B, C, D) of the vent wall 122 122ab will vary inaccordance with the design specifications for the system 100. The designspecification may take into account one or more parameters, such astemperature, humidity, velocity, gas composition, fuel type, or exhaustgas mixture. The system 100 dimensions should be configured toconcentrate and capture at least 85% of the high molecular weight gases.The at least one opening 122c is positioned at a height (A) such thatthe high molecular weight gases 112 have spun around the exhaust stack102 approximately fifteen to twenty times or more. In one example, theat least one opening 122c is positioned at a height (A) above the bottomof the exhaust stack 102 approximately equal to three diameters (3×D) ofthe exhaust stack 102, the annular space or gap 124 has an area (B) ofapproximately 10% of a cross-sectional area of the exhaust stack 102,and the bottom lower portion 122a 122b of the vent wall 122 122abextends down a distance (C) approximately equal to one half diameter(0.5×D) of the exhaust stack 102.

The system 100 may also include other components, such as a tank (504,FIG. 5) connected to the transfer pipe 128 to store the removed highmolecular weight gases 112, a compressor attached to the transfer pipe128 to compress the removed high molecular weight gases 112 (506, FIG.5), a motor (not shown) attached to the vent wall 122 122ab that adjustsa size of the annular space or gap 124 based on one or more parameters(e.g., temperature, humidity, velocity, gas composition, fuel type, orexhaust gas mixture, etc.), and/or one or more sensors (not shown)attached to the blower 106, exhaust stack 102, interior vent 122 ortransfer pipe 128. A controller (not shown) can be communicably coupledto the motor (not shown) and the one or more sensors to adjust the size(B) of the annular space or gap 124 using the motor based on one or moreparameters detected by the one or more sensors. As previously discussed,one or more bubble trays (508, FIG. 5) containing sodium hydroxide canbe attached to the transfer pipe 128 or tank such that the removed CO₂is combined with the sodium hydroxide to produce sodium carbonate.

Referring now to FIGS. 2A, 2B and 2C, a cross-sectional side view (FIG.2A), a cross-sectional top view at cross section E-E (FIG. 2B) and across-sectional bottom view at cross section F-F (FIG. 2C) of the system200 for separating high molecular weight (HMW) gases 112 in an exhauststack 102 from an exhaust gas 104 of a combustion source in accordancewith one embodiment of the present invention are shown. A blower 106 isattached to an intake 108 of the exhaust stack 102 to receive theexhaust gas 104 from the combustion source (502, FIG. 5) and create atangential flow 110 of the exhaust gas 104 within the exhaust stack 102.The blower 106 imparts sufficient centrifugal force on the exhaust gas104 to concentrate the high molecular weight gases 112, such as CO₂ orother gases having a higher molecular weight greater than N₂ or O₂(e.g., greater than 35), along the inner perimeter or surface 114 of theexhaust stack 102. Typically, the blower 106 causes the exhaust gases104 to spin around the interior of the exhaust stack 102 at least fivetimes within a height approximately equal to one diameter (D) of theexhaust stack 102.

As shown, the blower 106 is external to the exhaust stack 102 and isconnected to the intake 108 of the exhaust stack 102 with a first pipe116. A second pipe 118 connects the blower 106 to the bottom of theexhaust stack 102 at a point 120 approximately opposite to the intake108 and in line with the tangential flow 110 in order to create thesufficient centrifugal force on the exhaust gas 104. The use of astationary tubulator, or spin vanes, or actual in-stack centrifuge maybe necessary in addition to the blower 106.

An interior vent 122 within the exhaust stack 102 collects the highmolecular weight gases 112 concentrated along the inner surface 114 ofthe exhaust stack 102. The interior vent 122 includes: (i) a vent wall122ab having a top portion 122a attached to the interior surface 114 ofthe exhaust stack 102 along the entire inner perimeter of the exhauststack 102 (e.g., the top portion 122a is attached to the inner surface114 along any side cross section of the exhaust stack 102) and a lowerportion 122b that extends downward into the exhaust stack 102 to form anannular space or gap 124 between the vent wall 122 122ab and theinterior surface 114 of the exhaust stack 102; (ii) at least one opening122c in the interior surface 114 of the exhaust stack 102 between thetop 122a and bottom lower 122b portions of the vent wall 122 122ab; and(iii) a bustle 202 attached to or integrated into the exhaust stack 102between the at least one opening 122c in the inner surface 114 of theexhaust stack 102 and a transfer pipe 128. The transfer pipe 128 isconnected to bustle 202 to remove the high molecular weight gases 112from the interior vent 122 122ab. The at least one or more openings 122ccan be holes, slots, or any other geometrically shaped passageway.Moreover, more than one transfer pipe 128 can be used. The lower portion122b of the vent wall 122 122ab can be substantially parallel to theinterior surface 114 of the exhaust stack 102, curved or angled withrespect to the interior surface 114 of the exhaust stack 102. Note thatthe top portion 122a of the interior vent 122 122ab does not have to bealigned with a horizontal plane of the exhaust stack 102. For example,the top portion 122a can be angled from the horizontal plane inaccordance with the tangential flow 110 (top portion 122a on theopposite side of the exhaust stack 102 from the opening 122c positionedlower than the top portion 122a adjacent to the opening 122c). Forexample, the top portion 122a can form one or more spirals down from theone or more openings 122c. In addition, an optional baffle or guide 122dproximate to the at least one opening 122c can be used to direct theflow of the high molecular weight gases 112 from the interior vent 122into the transfer pipe 128. The baffle or guide 122d can be straight,angled, curved or any other shape and orientation to more efficientlyguide the high molecular weight gases 112 into the transfer pipe 128.

The dimensions (A, B, C, D) of the vent wall 122 122ab will vary inaccordance with the design specifications for the system 200. The designspecification may take into account one or more parameters, such astemperature, humidity, velocity, gas composition, fuel type, or exhaustgas mixture. The system 200 dimensions should be configured toconcentrate and capture at least 85% of the high molecular weight gases.The at least one opening 122c is positioned at a height (A) such thatthe high molecular weight gases 112 have spun around the exhaust stack102 approximately fifteen to twenty times or more. In one example, theat least one opening 122c is positioned at a height (A) above the bottomof the exhaust stack 102 approximately equal to three diameters (3×D) ofthe exhaust stack 102, the annular space or gap 124 has an area (B) ofapproximately 10% of a cross-sectional area of the exhaust stack 102,and the bottom lower portion 122a 122b of the vent wall 122 122abextends down a distance (C) approximately equal to one half diameter(0.5×D) of the exhaust stack 102.

The system 100 may also include other components, such as a tank (504,FIG. 5) connected to the transfer pipe 128 to store the removed highmolecular weight gases 112, a compressor attached to the transfer pipe128 to compress the removed high molecular weight gases 112 (506, FIG.5), a motor (not shown) attached to the vent wall 122 122ab that adjustsa size of the annular space or gap 124 based on one or more parameters(e.g., temperature, humidity, velocity, gas composition, fuel type, orexhaust gas mixture, etc.), and/or one or more sensors (not shown)attached to the blower 106, exhaust stack 102, interior vent 122 ortransfer pipe 128. A controller (not shown) can be communicably coupledto the motor and the one or more sensors to adjust the size (B) of theannular space or gap 124 using the motor based on one or more parametersdetected by the one or more sensors. As previously discussed, one ormore bubble trays (508, FIG. 5) containing sodium hydroxide can beattached to the transfer pipe 128 or tank such that the removed CO₂ iscombined with the sodium hydroxide to produce sodium carbonate.

Now referring to FIGS. 3A, 3B and 3C, a cross sectional side view (FIG.3A), a cross-sectional top view at cross section E-E (FIG. 3B) and across-sectional bottom view at cross section F-F (FIG. 3C) of the system300 for separating high molecular weight (HMW) gases in an exhaust stack102 from an exhaust gas 104 of a combustion source in accordance withone embodiment of the present invention are shown. A blower 106 isattached to an intake 108 of the exhaust stack 102 to receive theexhaust gas 104 from the combustion source (502, FIG. 5) and create atangential flow 110 of the exhaust gas 104 within the exhaust stack 102.The blower 106 imparts sufficient centrifugal force on the exhaust gas104 to concentrate the high molecular weight gases 112, such as CO₂ orother gases having a higher molecular weight greater than N₂ or O₂(e.g., greater than 35), along the inner perimeter or surface 114 of theexhaust stack 102. Typically, the blower 106 causes the exhaust gases104 to spin around the interior of the exhaust stack 102 at least fivetimes within a height approximately equal to one diameter (D) of theexhaust stack 102. As shown, the blower 106 is internal to the exhauststack 102. A second pipe 118 or channel connects the blower 106 to thebottom of the exhaust stack 102 at a point 120 approximately opposite tothe intake 108 and in line with the tangential flow 110 in order tocreate the sufficient centrifugal force on the exhaust gas 104. The useof a stationary tubulator, or spin vanes, or actual in-stack centrifugemay be necessary in addition to the blower 106.

An interior vent 122 within the exhaust stack 102 collects the highmolecular weight gases 112 concentrated along the inner surface 114 ofthe exhaust stack 102. The interior vent 122 includes: (i) a vent wall122ab having a top portion 122a attached to the interior surface 114 ofthe exhaust stack 102 along the entire inner perimeter of the exhauststack 102 (e.g., the top portion 122a is attached to the inner surface114 along any side cross section of the exhaust stack 102) and a lowerportion 122b that extends downward into the exhaust stack 102 to form anannular space or gap 124 between the vent wall 122 122ab and theinterior surface 114 of the exhaust stack 102; (ii) at least one opening122c in the interior surface 114 of the exhaust stack 102 between thetop 122a and bottom lower 122b portions of the vent wall 122 122ab; and(iii) a bustle 202 attached to or integrated into the exhaust stack 102between the at least one opening 122c in the inner surface 114 of theexhaust stack 102 and a transfer pipe 128. The transfer pipe 128 isconnected to bustle 202 to remove the high molecular weight gases 112from the interior vent 122. The at least one or more openings 122c canbe holes, slots, or any other geometrically shaped passageway. Moreover,more than one transfer pipe 128 can be used. The lower portion 122b ofthe vent wall 122 122ab can be substantially parallel to the interiorsurface 114 of the exhaust stack 102, curved or angled with respect tothe interior surface 114 of the exhaust stack 102. Note that the topportion 122a of the interior vent 122 does not have to be aligned with ahorizontal plane of the exhaust stack 102. For example, the top portion122a can be angled from the horizontal plane in accordance with thetangential flow 110 (top portion 122a on the opposite side of theexhaust stack 102 from the opening 122c positioned lower than the topportion 122a adjacent to the opening 122c). For example, the top portion122a can form one or more spirals down from the one or more openings122c. In addition, an optional baffle or guide 122d proximate to the atleast one opening 122c can be used to direct the flow of the highmolecular weight gases 112 from the interior vent 122 into the transferpipe 128. The baffle or guide 122d can be straight, angled, curved orany other shape and orientation to more efficiently guide the highmolecular weight gases 112 into the transfer pipe 128).

The dimensions (A, B, C, D) of the vent wall 122 122ab will vary inaccordance with the design specifications for the system 300. The designspecification may take into account one or more parameters, such astemperature, humidity, velocity, gas composition, fuel type, or exhaustgas mixture. The system 300 dimensions should be configured toconcentrate and capture at least 85% of the high molecular weight gases.The at least one opening 122c is positioned at a height (A) such thatthe high molecular weight gases 112 have spun around the exhaust stack102 approximately fifteen to twenty times or more. In one example, theat least one opening 122c is positioned at a height (A) above the bottomof the exhaust stack 102 approximately equal to three diameters (3×D) ofthe exhaust stack 102, the annular space or gap 124 has an area (B) ofapproximately 10% of a cross-sectional area of the exhaust stack 102,and the bottom lower portion 122a 122b of the vent wall 122 122abextends down a distance (C) approximately equal to one half diameter(0.5×D) of the exhaust stack 102.

The system 100 may also include other components, such as a tank (504,FIG. 5) connected to the transfer pipe 128 to store the removed highmolecular weight gases 112, a compressor attached to the transfer pipe128 to compress the removed high molecular weight gases 112 (506, FIG.5), a motor (not shown) attached to the vent wall 122 122ab that adjustsa size of the annular space or gap 124 based on one or more parameters(e.g., temperature, humidity, velocity, gas composition, fuel type, orexhaust gas mixture, etc.), and/or one or more sensors (not shown)attached to the blower 106, exhaust stack 102, interior vent 122 ortransfer pipe 128. A controller (not shown) can be communicably coupledto the motor and the one or more sensors to adjust the size (B) of theannular space or gap 124 using the motor based on one or more parametersdetected by the one or more sensors. As previously discussed, one ormore bubble trays (508, FIG. 5) containing sodium hydroxide can beattached to the transfer pipe 128 or tank such that the removed CO₂ iscombined with the sodium hydroxide to produce sodium carbonate.

Referring now to FIG. 4, a flow chart of a method 400 for separatinghigh molecular weight gases in an exhaust stack from an exhaust gas of acombustion source in accordance with one embodiment of the presentinvention is shown. The following components are provided in block 402to perform the method 400: (a) a blower attached to an intake of anexhaust stack to receive the exhaust gas from the combustion source, (b)an interior vent within the exhaust stack comprising (i) a vent wallhaving a top portion attached to the interior surface of the exhauststack along the entire inner perimeter of the exhaust stack and a lowerportion that extends downward into the exhaust stack to form an annularspace or gap between the vent wall and the interior surface of theexhaust stack, and (ii) at least one opening in the interior surface ofthe exhaust stack between the top and bottom portions of the vent wall,and (c) a transfer pipe connected to the at least one opening in theinterior surface of the exhaust stack. A tangential flow of the exhaustgas within the exhaust stack is created using the blower in block 404.The blower imparts sufficient centrifugal force on the exhaust gas toconcentrate substantially all of the high molecular weight gases alongthe inner surface of the exhaust stack. The high molecular weight gasesconcentrated along the inner surface of the exhaust stack are collectedusing the interior vent in block 406. The high molecular weight gasesare removed from the interior vent using the transfer pipe in block 408.

Additional steps may include storing the removed high molecular weightgases in a tank (504, FIG. 5) connected to the transfer pipe,compressing the removed high molecular weight gases (506, FIG. 5),injecting the removed high molecular weight gases into a below-groundstorage, or flowing the removed CO₂ up through one or more bubble trayscontaining sodium hydroxide which causes the removed CO₂ to combine withthe sodium hydroxide to produce sodium carbonate (508, FIG. 5).

Now referring to FIG. 5, a block diagram of a system 500 incorporatingthe embodiments of the present invention is shown. As previouslydescribed, the combustion source 502 creates exhaust 104, which istransported to the exhaust stack 102 (not specifically illustrated inFIG. 5) of system 100, 200 or 300. Low molecular gas 130 exits theexhaust stack 100, 200 or 300. The high molecular weight gas 112 iscollected and removed from the exhaust stack 100, 200 or 300 for furtherprocessing (e.g., storage in a tank 504, compression followed by storage506, bubble trays to produce sodium carbonate 508, etc.). The highmolecular weight gas 112 can be used in other ways as will beappreciated and known by those skilled in the art.

The various illustrative logical blocks, modules, circuits, andalgorithm steps described herein may be implemented as electronichardware, computer software, or combinations of both, depending on theapplication and functionality. Moreover, the various logical blocks,modules, and circuits described herein may be implemented or performedwith a general purpose processor (e.g., microprocessor, conventionalprocessor, controller, microcontroller, state machine or combination ofcomputing devices), a digital signal processor (“DSP”), an applicationspecific integrated circuit (“ASIC”), a field programmable gate array(“FPGA”) or other programmable logic device, discrete gate or transistorlogic, discrete hardware components, or any combination thereof designedto perform the functions described herein. Similarly, steps of a methodor process described herein may be embodied directly in hardware, in asoftware module executed by a processor, or in a combination of the two.A software module may reside in RAM memory, flash memory, ROM memory,EPROM memory, EEPROM memory, registers, hard disk, a removable disk, aCD-ROM, or any other form of storage medium known in the art. Althoughpreferred embodiments of the present invention have been described indetail, it will be understood by those skilled in the art that variousmodifications can be made therein without departing from the spirit andscope of the invention as set forth in the appended claims.

What is claimed is:
 1. A method for separating high molecular weightgases from an exhaust gas of a combustion source comprising the stepsof: providing (a) a blower attached to an intake of an exhaust stack toreceive the exhaust gas from the combustion source, (b) an interior ventwithin the exhaust stack comprising (i) a vent wall having a top portionattached to the an interior surface of the exhaust stack along theentire inner perimeter of the exhaust stack and a lower portion thatextends downward into the exhaust stack to form a gap between the ventwall and the interior surface of the exhaust stack, and (ii) at leastone opening in the interior surface of the exhaust stack between the topand bottom portions of the vent wall, and (c) a transfer pipe connectedto the at least one opening in the interior surface of the exhauststack; concentrating the high molecular weight gases along the innersurface of the exhaust stack by creating a tangential flow of theexhaust gas within the exhaust stack using the blower, wherein theblower imparts sufficient centrifugal force on the exhaust gas toconcentrate substantially all of the high molecular weight gases alongthe inner surface of the exhaust stack; collecting the high molecularweight gases concentrated along the inner surface of the exhaust stackusing the interior vent; and removing the high molecular weight gasesfrom the interior vent using the transfer pipe.
 2. The method as recitedin claim 1, further comprising the steps of: storing the removed highmolecular weight gases in a tank connected to the transfer pipe;compressing the removed high molecular weight gases; or injecting theremoved high molecular weight gases into a below-ground storage.
 3. Themethod as recited in claim 1, wherein the high molecular weight gaseshave a molecular weight greater than
 35. 4. The method as recited inclaim 1, wherein the high molecular weight gases comprise CO₂.
 5. Themethod as recited in claim 4, further comprising the step of flowing theremoved CO₂ up through one or more bubble trays containing sodiumhydroxide which causes the removed CO₂ to combine with the sodiumhydroxide to produce sodium carbonate.
 6. The method as recited in claim1, wherein; the sufficient centrifugal force is provided by the blowerin combination with a stationary tabulator, spin vanes, or in-stackcentrifuge; and the blower is located inside or outside of the exhauststack.
 7. The method as recited in claim 1, further comprising providinga bustle attached to or integrated into the exhaust stack between the atleast one opening in the inner surface of the exhaust stack and thetransfer pipe.
 8. The method as recited in claim 1, wherein the lowerportion of the vent wall is substantially parallel to the interiorsurface of the exhaust stack, curved, or is angled with respect to theinterior surface of the exhaust stack.
 9. The method as recited in claim1, wherein the concentrating the high molecular weight gases along theinner surface of the exhaust stack comprises concentrating at least 85%of the high molecular weight gases are concentrated along the innersurface of the exhaust stack.
 10. The method as recited in claim 1,wherein the gap comprises an area of approximately 10% of across-sectional area of the exhaust stack.
 11. The method as recited inclaim 1, wherein the at least one opening is positioned such that thehigh molecular weight gases have spun around the exhaust stackapproximately fifteen to twenty times prior to reaching the at least oneopening.
 12. The method as recited in claim 1, wherein the blower causesthe exhaust gases to spin around the exhaust stack at least five timeswithin a height approximately equal to one diameter of the exhauststack.
 13. The method as recited in claim 1, wherein the at least oneopening is positioned at a height above the a bottom of the exhauststack approximately equal to three diameters of the exhaust stack. 14.The method as recited in claim 1, wherein the bottom lower portion ofthe vent wall extends down to a height above the a bottom of the exhauststack approximately equal to one half diameter of the exhaust stack. 15.The method as recited in claim 1, further comprising a motor attached tomoving the vent wall that adjusts to adjust a size of the gap.
 16. Themethod as recited in claim 15, wherein the motor step of moving is usedto adjust the size of the gap based on one or more parameters comprisingtemperature, humidity, velocity, gas composition, fuel type, or exhaustgas mixture.
 17. The method as recited in claim 15, further comprising:one or more sensors attached to the blower, exhaust stack, interior ventor transfer pipe; and a controller communicably coupled to the motor andthe one or more sensors, wherein the controller to adjusts the size ofthe gap using the motor based on one or more parameters detected by theone or more sensors.
 18. The method as recited in claim 9, whereinconcentrating the high molecular weight gases along the inner surface ofthe exhaust stack comprises concentrating substantially all of the highmolecular weight gases along the inner surface of the exhaust stack. 19.The method as recited in claim 16, further comprising: sensing the oneor more parameters of the exhaust gas at the blower, exhaust stack,interior vent, or transfer pipe; and controlling the step of moving thevent wall to adjust the size of the gap based on the sensed one or moreparameters.
 20. A method for removing high molecular weight gases froman exhaust stream, comprising: introducing exhaust gas tangentially intoan exhaust stack; concentrating high molecular weight gases toward aninner surface of the exhaust stack by spinning the exhaust gas andimparting centrifugal force; and removing gases from along the innersurface of the exhaust stack; wherein the spinning the exhaust gas andimparting centrifugal force comprises accelerating exhaust gas that isspinning within the stack; and wherein the accelerating exhaust gascomprises removing exhaust gas tangentially from one side of the exhauststack and blowing it tangentially back into the exhaust stack on a sideopposite the one side.